Seating assemblies for vehicles typically include a seatback to support the back of an occupant in an upright seated position and various reclined positions. Seatbacks of these vehicle seating assemblies are commonly designed to support an occupant upon acceleration, change in direction, and collision of the vehicle, such that the seatbacks are substantially rigid in construction and lack adequate adjustment features, particularly in meeting the needs of varying occupant body shapes, sizes, and relaxation positions.